Linear alkylphenol sulfate-sulfonate phosphate-free detergent actives

ABSTRACT

Heavy duty detergent active materials capable of heavy duty washing performance in the absence of phosphate builders are provided, the materials comprising alkylphenol sulfate-sulfonate compounds in which the alkyl groups are linear of 16-24 carbon atoms,.

United States Patent Danzik et al.

[451 Oct. 10, 1972 [54] LINEAR ALKYLPHENOL SULFATE- SULFONATEPHOSPHATE-FREE DETERGENT ACTIVES [72] Inventors: Mitchell Danzik,Pinole; Ralph House, El Sobrante, both of Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

22 Filed: May 5,1970

21 App1.No.: 34,885

[52] US. Cl. ..260/457, 252/531, 252/550 [51] Int. Cl ..C07c 141/00 [58]Field of Search ..260/457 [5 6] References Cited UNITED STATES PATENTS2,106,716 2/1938 Bruson ..260/457 X FOREIGN PATENTS OR APPLICATIONS6,709,714 1/1968 Netherlands ..260/458 Primary ExaminerLeon ZitverAssistant Examiner-L. B. De Crescente Attorney-J. A. Buchanan, Jr., G.F. Magdeburger, John Stoner, Jr. and J. T. Brooks [5 7] ABSTRACT 4Claims, No Drawings LINEAR ALKYLPHENOL SULFATE-SULFONATE PHOSPHATE-FREEDETERGENT ACTIVES BACKGROUND OF THE INVENTION This invention isconcerned with novel linear alkylphenol sulfate-sulfonate compoundswhich are effective in detergent applications as detergent actives.

Increased concern over water pollution has produced significant changesin household detergents. Initially, major emphasis has been placed onproducing biodegradable surface-active components for detergents. Theshift to linear surface-active materials, including linear alkylbenzenesulfonate (LAS) and alphaolefin sulfonates, etc., has reduced pollutionattributed to nonbiodegradability.

However, the above-mentioned surface-active materials are inadequate interms of soil removal in the absence of phosphate builders. Increasingevidence appears to indicate that phosphates contribute to the growth ofalgae in the nations streams and lakes. This algae growth poses aserious pollution threat to the maintenance of clear, good domesticwater supplies.

Consequently, there has developed a need for detergent active materialswhich will function successfully in the absence of phosphate builders.Recently, certain non-phosphate building materials have been proposed asreplacements for the phosphates. Thus, materials such as the polysodiumsalts of nitrilotriacetic acid, ethylene diamine tetraacetic acid,'copolymers of ethylene and maleic acid, and similar polycarboxylicmaterials have been proposed as builders. These materials, however, whenemployed with conventional detergent actives such as LAS, have, for onereason or another, not proved to be quite as effective as phosphates indetergent formulations. For example,

some of the materials have proven to be insufficiently biodegradable tomeet present and anticipated requirements.

It is therefore desirable to provide compounds which are effective asdetergent active materials in the absence of phosphate builders and aresufficiently biodegradable that their use does not contribute foam tothe water supply.

In addition, in the past, with heavy duty detergents, it has beenthought that to achieve good soil removal it was necessary to maintain ahigh pH in washing solutions. This concept, which began with thestrongly alkaline laundry soaps, has continued to the present dayLAS-phosphate combinations which are in widespread use in heavy dutydetergent formulations. One apparent reason for this is that thealkylbenzene sulfonate detergents are not effective in heavy dutydetergent formulations in the absence of a builder. The phosphatebuilders, for example, must be employed at a pH greater than 9 to beeffective, and even the newer builders such as sodium nitriloacetatehave a pH of about 9 in solution. The advantages to be gained with heavyduty detergents which may be employed at neutral pH are many.Deleterious effects from skin contact are lessened. Enzyme-type soillooseners may be more easily combined in neutral solutions. Injury tofabrics is minimized. It is, therefore, desirable to provide detergentactive materials which, in addition to the previously mentionednon-polluting characteristics, achieve their maximum detergency at ornear neutral pH.

The formulation of liquid heavy duty detergent compositions achievesmany desirable results. They are easy to package and measure, and theiruse opens the possibility of automatic dispensing in washing machines.However, in the past it has been impracticable to formulate heavy dutydetergents in liquid form because of the insufficient solubility of theinorganic ingredients (phosphate builders, etc.) required for heavy dutyapplications and the high cost of organic substitutes for such inorganicingredients. It is therefore highly desirable to provide detergentactive materials having good water solubility and which, because oftheir excellent detergency without builders, can be formulated intoeffective, reasonably priced, heavy duty liquid detergent formulations.

SUMMARY OF THE INVENTION Heavy duty detergent materials are providedwhich comprise alkylphenol sulfate-sulfonates of the formula R s 03X inwhich R is a substantially linear alkyl group of from about 16 to 24carbon atoms and X is H or a water soluble salt-forming cation.

The compounds of this invention do not require the presence of a builderto achieve good heavy duty detergency, and while they are effective overa broad pH range, reach their maximum effectiveness at a pH near neutralin detergent solutions. Thus washing at a pH of 6.5 to 8.0, preferably6.5 to 7.5, will give maximum soil removal while securing the previouslymentioned advantages which inhere in the use of neutral washingsolutions. Further, the compounds may be easily compounded intoeffective liquid heavy duty formulations because of the substantialsolubility of the compounds in water and because of the lack of need forlarge adjunctive portions of inorganic materials such as builders.

DESCRIPTION OF PREFERRED EMBODIMENTS The salt-forming cation X may beany of numerous materials such as alkali metal, alkaline earth metal,ammonium, or various organic cations. Examples of suitable organiccations include nitrogen-containing organic cations such asdiethanolammonium and triethanolammonium cations. The alkali metalcations are preferred, and sodium ions are particularly preferred.

The alkyl groups represented by R are, as previously noted,substantially linear, although the presence of a random methyl radicalupon the linear chain, for example, may not adversely affect theperformance of the compounds. Alkyl radicals representative of R includehexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl,docosyl, tricosyl, and tetracosyl. The preferred compounds will have asalkyl substituents octadecyl, nonadecyl, and eicosyl groups.

The alkylphenols which are suitable for the preparation of the compoundsof this invention are prepared by conventional techniques. Suchtechniques include thermal and catalytic alkylation of phenol witholefms, al-

cohols and haloparaffins. Catalytic methods include the use ofFriedel-Crafts catalysts such as aluminum chloride, zinc chloride, etc.,and various acid catalysts and clay catalysts.

The alkyl groups are generally derived from alcohols, olefins, orhaloparaffins. The position of the attachmentrof the aromatic nucleus onthe alkyl chain may beat any point. with alpha olefins the predominantpoint of attachment of the alkylation product will be end groupattachment-thatis, either at the l or 2 but principally at the 2position of the chain. On the. other hand, with an isomerized mixture ofolefins or olefins derived from haloparaffms which have, in turn, beenproduced by halogenation of paraffins, the position of the double bondwill be generally completely random on the chain, and thus thecorresponding aromatic nucleus attachment will be random.

The sulfonation and sulfation of the alkylphenols to produce thecompounds of this invention is accomplished by reacting the alkylphenolwith a sulfonating agent capable of (1) converting the aromatic hydroxylradical to a sulfate and (2).forming a ring-substituted SO H underconditions such that the reaction product contains both an -OSO H and anSO H radical attached to the aromatic nucleus. The preferred sulfonatingagent satisfying these reaction prerequisites is sulfur trioxide. Thesulfur trioxide may be employed in mixtures with an appropriate liquidsolvent such as a chlorinated hydrocarbon or liquid 80,. Complexed 80;,may also be used to effect the reaction. Typical complexing agents aredioxane and dimethylaniline, triethylamine, etc.

In contrast,the reaction of the alkylphenol with sulfuric acid,oleum,-or chlorosulfonic acid under conventional sulfonationconditionsdoes not result in any appreciable yields of the correspondingsulfate-sulfonate.

The alkylphenol sulfate-sulfonate compounds .of this invention .thusaresuitably prepared by the reaction of an alkyl-phenol with sulfurtrioxide. The reaction is carriedout in an anhydrous inert solvent suchas the chlorinated hydrocarbons, e.g., dichloroethane. The quantity ofsulfur trioxide to be used should equal or exceed 2 moles per mole ofalkylphenol for 100% conversion of the. latter. Mole ratios of S0,, toalkylphenol I ashigh as 10:1 may be employed, but preferably the ratiois in the range of 3:1 to 5:1. At mole ratios below 2:1, some of thedesired alkylphenol sulfate-sulfonate will be formed, but depending onthe mole ratio used, substantial amounts of mono sulfonated'materialwill be formed. Reaction temperatures are generally in the range of -lto 10 C, preferably about to 0 C. Alkylphenol, dissolved in the solventis cooledto the reaction temperature and then 80;, dissolved in the samesolvent is added. The reaction is exthermic, and cooling meansmust beemployed to keep the temperature within the desired range. The rate ofaddition of S0, is such thatthe cooling means can hold this temperature.Thus the time required for reaction varies as to efficiency of cooling,size of reaction mass, etc., but generally the addition will be completewithin to 120 minutes for small sized batches. Continuous procedureispreferred for large batches. In continuous processing, the reactants,dissolved in an appropriate solvent and cooled to reaction temperature,are charged to a cooled tubular reactor, wherein the average residencetime is only a few minutes or less.

After sulfonation, the .reaction product may be neutralized with awater-soluble, salt-formingcationic neutralizing agent, usually a metaloxide or hydroxide, and more preferably an alkaline earth metal oralkali metal hyroxide. The alkali metal hydroxides are preferred, andsodium hydroxide is most preferredsln addition to the inorganic basesdescribed above, the neutralizing agent may be any of various organicbases. Sufficient base is added to neutralize both acid sites, that isabout two moles. The final of the neutralized mixture should be about 7,butpl-l values within the range of 6 to 8 are satisfactory.

Following neutralization, the inert organic solvent is removed forreuse. Thismay be done by phase separation, or preferably bydistillation. The organic solvent free material comprises an aqueoussolution of the organic surface active materials and any inorganic salt,such as sodium sulfate. The neutralized product, which will contain asubstantial quantity of waterand from 1 to 4 parts of a normallyinorganic sulfate from the neutralization of excess SO, (e.g., Na,SO maybe used, as is, in combination with conventional detergent additives. toformulate liquid heavy duty detergents. Altematively, water may beremoved in any quantity to complete dryness by. conventionalconcentration techniques such as evaporation, distillation, drum drying,etc., to yield a concentrated solution,-a slurry, or a dry particulatesolid which .may then be blended to form a heavy duty detergent.

The solid product isolated as described above may be desalted by theusual procedures as used in the alkyl benzene sulfonate art. In thismethod thesolid material is mixed with about a /30 alcohol/watersolution. The insoluble inorganic sulfate is removed by filtration, andthe organic surfactant may be used as such or isolated by evaporation ofthe solvent. The liquid concentrates and slurries may be treated insimilar fashion with allowance made for the quantity of water alreadypresent. These desalting procedures give a detergent product that isessentially free of inorganic salt.

The following examples describe the preparation of the compounds of thisinvention.

Example 1 Preparation of Octadecylphenol Sulfate- Sulfonate i To a 20ml. reaction vessel fitted witha septum, drying tube, thermometer, and amagnetic stirring bar, was charged 1.0 g. (0.00289 mols) of a Calkylphenol which had been prepared by thermal. alkylation of phenolwith a linear C alpha olefin accordingto the procedure of U.S. Pat. No.-3,423,474. A 10 ml. portion of dry 1,2-dichloroethanewas charged to thereaction flask. The solution was flushed with nitrogen and stirring wasbegun. The solution was cooled -to -10C in an ice-acetone bath.

A solution of 1.0 ml anhydrous sulfur trioxide (1.9. g, 0.0237 mols) in5 ml. of dry 1,2-dichloroethane was cooled to about 0 C. The solutionwas injected into the reaction solution with a syringe at such a rate asto maintain the reaction temperature at about 0 C. After the additionwas complete, the cooling bath was removed, and the reaction mixture wasallowed .to

warm to room temperature over a period of about 15.

minutes. It was then added to 50 .ml. of 0.5 N NaOH solution andtitrated to a pH of about 10 with additional 0.5 N NaOH. The mixture wasthen placed upon a rotary evaporator, and the organic solvent wasremoved under vacuum at 2530 C. The remaining water solution was dilutedto 500 ml. and titrated by a standard l-lyamine procedure giving about a90% yield of octadecylphenol sulfate-sulfonate. Dilute acid hydrolysisfollowed by titration showed that the primary product contained bothsulfate and sulfonate groups in substantially equal amounts; that is, itwas an alkylphenol sulfate-sulfonate.

An infrared spectrum of the product showed strong adsorption in thel,020-l,070 cmand in the 1 ,200-1 ,280 cmregions.

Example 2 Preparation of Additional Linear AlkylphenolSulfate-Sulfonates.

Following the general procedure of Example 1, materials were prepared byemploying as precursors a series of alkylphenols in which the alkylgroups were linear and the major ring attachment was at the two carbonatom of the alkyl group. Additionally, alkylphenols were used in whichthe attachment of the aromatic nucleus was random on the alkyl chain.Alkylphenols having alkyl groups of l4, 16, 20, and 22 carbon atoms andmixtures of alkylphenols containing 18, 19, alkyl carbons and 18, 20,and 22 alkyl carbons were reacted with sulfur trioxide. Analysis was bythe method shown in Example 1.

Example 3 Drying of Aqueous Alkylphenol Sulfate- Sulfonate Solution Anaqueous solution of octadecylphenol sulfate-sulfonate prepared asdescribed in Example 1 was neutralized with sufficient sodium hydroxideto give a pH of 7. The dichloroethane was removed by heating undervacuum at about 25-30 C. The temperature was then raised, and all of thewater was removed to leave a particulate solid mass weighing 5.15 g.Analysis showed that this material contained 31 percent octadecylphenolsulfate-sulfonate, a small amount of water, and the remainder sodiumsulfate. The above isolated solid was a free-flowing powder.

The compounds of this invention are useful as heavy duty detergentactives. in the past, heavy duty detergent formulations useful forremoving soil from textiles have comprised an organic surfactant(detergent) and an inorganic phosphate builder; the phosphate beingpresent by weight, in an amount of from one to four times that of thedetergent. The compounds of the present invention are excellent soilremovers without the aid of any phosphate builder. That is, thecompounds of this invention satisfy all need for both organic surfactantand builder in the final heavy duty detergent formulation. One way thatthis may be accomplished is by preparing a mixture of the sulfate-subfonate materials of the instant invention and an inert material, e.g.water, sodium sulfate, sodium carbonate, etc. Such mixtures may containany amount of sulfatesulfonate in excess of about 10 percent, preferably15 percent or more. One useful composition comprises from to 50 percentsulfate-sulfonate and the remainder, sodium sulfate. Many othercombinations make useful formulations and may be either liquid solutionsor particulate solids.

As heavy duty detergents, it is contemplated that the sulfate-sulfonatecompounds will be used in wash water at concentrations of about 0.01percent to about 0.10 percent. This is within the same range ofconcentrations as are employed with the present day commercialdetergents. In other words, the soil removal properties of the presentcompounds are essentially equivalent to the soil removal properties ofan equal amount of the current commercial surfactant combined with atleast an equal amount of phosphate.

Detergency of the compounds of the present invention is measured bytheir ability to remove natural sebum soil from cotton cloth. By thismethod, small swatches of cloth, soiled by rubbing over face and neck,are washed with test solutions of detergents in a miniature laboratorywasher. The quantity of soil removed by this washing procedure isdetermined by measuring the reflectances of the new cloth, the soiledcloth, and the washed cloth, the results being expressed as per centsoil removal. Because of variations in degree and type of soiling, inwater and in cloth, and other unknown variables, the absolute value ofper cent soil removal is not an accurate measure of detergenteffectiveness and cannot be used to compare various detergents.Therefore, the art has developed the method of using relative detergencyratings for comparing detergent effectiveness.

The relative detergency ratings are obtained by comparing andcorrelating the per cent soil removal results from solutions containingthe detergents being tested with the results from two defined standardsolutions. The two standard solutions are selected to represent adetergent system exhibiting relatively high detersive characteristicsand a system exhibiting relatively low detersive characteristics. Thesystems are assigned detergency ratings of 6.3 and 2.2, respectively.

By washing portions of each soiled cloth with the standardizedsolutions, as well as with two test solutions, the results can beaccurately correlated. The two standard solutions are identical informulation but are employed at different hardnesses.

Standard Solution Fonnulation The standard exhibiting high detersivecharacteristics (Control B) is prepared by dissolving the aboveformulation (1.0 g.) in 1 liter of 50 ppm hard water (calculated astwo-thirds calcium carbonate and one-third magnesium carbonate). The lowdetersive standard (Control A) contained the formulation (1.0 g.)dissolved in one liter of ppm water (same basis).

A miniature laboratory washer is so constructed that four differentsolutions can be used to wash different parts of the same swatch. Thisarrangement ensures that all four solutions are working on identicalsoil (natural facial soil). Relative detergency ratings (RDRs) arecalculated from soil removals (SRs) according to the equation:

% Telt Cuntrol A Detergency results obtained on a variety of the subjectcompounds are given in the following table. Each value shown is theaverage of at least fourtests- For comparison, the detergency rating isgiven for a linear alkylbenzene sulfonate (LAS) (having from 11 to 14carbon straight chain alkyl groups) both with and without phosphatebuilder.

Each formulation tested comprised 25 weight percent'of the test materialalong with 1 percent carboxymethylcellulose, 7 percent sodium silicate,8 percent water, and 59 percent sodium sulfate. The LAS comparisonformulations were prepared in the same way except that. in Test 2 40percent of the sodium sulfate was replaced by an equal amount of sodiumtripolyphosphate and only 20 percent of LAS was used. Theformulationswere tested at several concentrations in water ranging from0.1 to 0.2 weight percent. These concentrationswere chosen in order tobracket the 0.15 percent concentration typical of household use. Thetest results were obtained at a pH of 7, except for the two LASexamples,which were run at a pH of 9 (without phosphate) and 10(with phosphate).

TABLE Detergent Effectiveness of Linear Alkylphenol Sulfate- SulfonatesRelative Detergency Ratings (at indicated formulation concentrations)These data show that the alkylphenol sulfate-sulfonates of thisinvention are greatly superior to phosphate-free LAS and aresubstantially equivalent to phosphate-built LAS in detergency. Moreparticularly, it may be noted that the compounds are very effectivenon-phosphate detergents and are particularly effective in hard water,

It will be understood that the effective compositions of this inventioninclude those materials which com-.

prise a mixture of the alkylphenol sulfate-sulfonates in which the alkylgroups vary in their carbon chain length between 16 and 24. Thus in mostinstances a single species in this respect will not be practicalcommercially and generally most effective compositions will comprisemixtures wherein at least 10 and preferably at preferably from about 18to 20 carbon atoms.

The alkylphenol sulfate-sulfonates may be employed in combination withother detergent active materials.

They are particularly effective with other dianionic' materials,examples of which include linear alkyl and alkenyl disulfates anddisulfonates. A particularly useful class of materials for use indetergent active combinations is that of linear 2-alkenyl or linear2-alkyl l ,4-

butane diol disulfates in which the alkenyl or alkyl groups contain from15 to 20 carbon atoms. Another particularly effective class of materialsare the alkylphenol disulfonates described in our previously mentionedcopending patent application.

In employing the detergent active materials of this invention indetergent compositions, they may be formulated with additionalcompatible ingredients being optionally incorporated to enhance thedetergent properties. Such materials may include but are not limited toanticorrosion, antiredeposition, bleaching and sequestering agents, andcertain organic and inorganic alkali metal and alkaline earth metalsaltssuch as inorganic sulfates, carbonates, or borates. Also nonphosphatebuilders may be included in the composition. Examples of these buildersinclude the sodium salts of nitrilotriacetic acid, ethylene diaminetetraacetic acid, and ethylene-maleic acid copolymers, etc. Also smallquantities of phosphate builders may be included in the compositions,although, of course, they are not necessary for effective detergency.

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that modifications and variations of the illustrativeexamples may be made in the practice of the invention within the scopeof the following claims.

We claim:

1. A compound of the formula:

OSOaX in which R is a linear alkyl radical of 16 to 24 carbon atoms andX is hydrogen'or a cation selected from the group consisting of alkalimetal, alkaline earth metal, ammonium, diethanolammonium andtriethanolammonium cations.

2. The compound of claim 1 in which R is an alkyl radical of 18 to 20carbon atoms.

3. The compound of claim 1 in which X is'an alkali metal cation.

4. The compound of claim 3 in which X is Na.

2. The compound of claim 1 in which R is an alkyl radical of 18 to 20carbon atoms.
 3. The compound of claim 1 in which X is an alkali metalcation.
 4. The compound of claim 3 in which X is Na.